I did some online research and found that the caterpillar turns into this spectacular Black Swallowtail Butterfly. Some people grow parsley and other related plants such as dill and Queen Annes Lace just to attract the butterflies, which in turn will lay their eggs that will turn into the caterpillars. A beautiful circle of life.
If you don't mind getting a little creeped out, watch this video of the worm having a magnificent lunch.
Turn up the volume and you can hear the crunching!